
Principle Investigator:
PD Dr. Volker Heussler, Bernhard-Nocht-Institute (BNI)
Background:
Cysteine proteases play a crucial role in the infection of the liver by Plasmodium sporozoites, in parasite development in liver cells and in the liberation of the fully developed liver merozoites. Additionally, intra- and extracellular Plasmodium parasites might be exposed to host cell proteases. Therefore, a tight and protease-specific regulation must be critical for the survival of the parasites and it is likely that Plasmodium parasites have evolved mechanisms to counteract proteolytic digestion. Short-term regulation of parasite as well as host proteases can be mediated by specific parasite-derived inhibitors. A prominent example is chagasin, which is expressed by Trypanosoma cruzi and was the first identified member of a new superfamily of reversible, tight-binding cysteine protease inhibitors. Chagasin-like inhibitors (also termed ICPs for inhibitor of cysteine proteases) are suggested to regulate both endogenous parasite-derived cysteine proteases (T. brucei, T. cruzi, P. falciparum, E. histolytica) and/or host cell proteases (L. mexicana, P. aeruginosa, P. falciparum). We have identified a chagasin-like inhibitor of the rodent parasite P. berghei and named it PbICP for P. berghei Inhibitor of Cysteine Proteases. PbICP consists of a C-terminal chagasin-like domain and a long N-terminal extension domain with an unknown function. Experiments with recombinantly expressed PbICP revealed that the inhibitor activity is maintained after deletion of the N-terminal extension region. In contrast to chagasin, PbICP does not inhibit cathepsin B but, similar to chagasin, it is a very potent inhibitor of human cathepsin L and papain.
Due to the interdisciplinary nature of the project, the graduate student will work in a joint appointment between the labs of PD Dr. Volker Heussler (BNI), Prof. Rolf Hilgenfeld (Uni Lübeck and Prof. Christian Betzel (Uni Hamburg).
Homepage Heussler
1.03.2012, 17 pm
by Prof. Dr. Gregers Anderson, Aarhus University, Denmark